1. Field of the Invention
This invention relates to an emulsion breaking material applicable to a treatment of an emulsion of emulsifiable compound, especially of an emulsified oil.
2. Description of the Prior Art
Severe social problems have recently been raised about public hazards such as water pollution and sea corruption caused by the waste water containing emulsifiable compounds, especially by the waste water containing animal fats, plant and/or mineral oils.
Among the treatments of the waste water containing said compounds, the removal of an oil component from the waste water containing an emulsified oil, such as an oil emulsified by the addition of surfactant or extremely small oil particles, is very hard when compared to the removal of dispersed oil particles having larger diameters.
The above-described waste water is discharged from factories of various industries such as machinery industry, chemical industry, steel industry, as a matter of course, and food industry, paint industry and textile industry as well.
As a method for the treatment of the waste water containing an emulsified oil, hitherto, there are mentioned electrolytic process; oil-water separation by pressure/foam separation, flocculation precipitation or filtration with an addition of salting-out reagents, flocculating reagents or cohesive reagents; or extraction of oil using solvents.
Every method, however, has some disadvantages, for instance,
(a) large scale equipment or time-consuming treatments are required to purify the waste water up to the undetectable concentration of oil.
(b) some of the above-mentioned methods necessitate other subsequent treatments since they are not efficient enough to decrease the oil concentration less than 5 ppm of mineral oils and 30 ppm of animal and plant oils as suggested by the Country's Pollution Control Standards (hereinafter referred to as "CPCS").
Furthermore, there is a method proposed in which amine derivatives liquid at normal temperature or those modified to have an affinity for water as used as emulsion breakers; however, such breakers are only effective when homogeneously mixed with water. The use of a mixing apparatus is essential for this method, and nevertheless, it is difficult to reduce the COD of the waste water by this method, which necessitates the secondary treatment of the waste water with activated charcoal.
For the purpose of improving the disadvantages of these treating methods, some methods have been proposed (for example, refer to Japanese Pat. Laid-open No. 51-79959, and No. 51-120050) in which composite of fibrous substance and inorganic compounds are used as the treating material, but they are also unsatisfactory in the removal of emulsifiable compounds (refer to the comparative example 1 described later). Therefore, the development of a treating material which can treat the emulsifiable compounds practically effectively, easily industrially, has been desired.